The present invention relates to imaging apparatus, and more particularly relates to high-definition electronic still imaging apparatus having a liquid crystal view finder and also to imaging apparatus in which both dynamic video image taking and high-definition electronic still image taking are made possible.
Because of the rapid spreading of personal computers in recent years, there is an increasing demand for digital cameras (electronic still camera) as an image input equipment. Also, high-quality image recording apparatus such as digital video camera are widely used as a recording equipment of dynamic images. Since, in these image input equipment, the number of pixels of an image sensor is a major factor for determining the resolution of taken images, the pixel number tends to increase from year to year. Some digital cameras in the recent market are sold even with a large number of pixels of 4,000,000 or more. The digital cameras are generally provided with a real-time electronic finder as a means for confirming the extent of object to be photographed. Further it is not uncommon for a digital camera to be capable also of taking dynamic images.
To achieve the function of dynamic image recording or electronic finder, images must be taken in real time (30 frames per second or more) with each having a number of pixels of the order of one of several to several-ten parts of the pixel number of image sensor. In an image sensor having several million pixels, however, it is difficult, because of operation clock, to read all the pixels at the rate of 30 frames per second. For this reason, methods have been suggested of processing thinned out signals to generate a reduced image by using an imaging apparatus which has a function in specific mode to intermittently read only a required number of pixels from the image sensor.
Examples thereof include a single-sensor imaging apparatus as disclosed in Japanese patent application laid-open Hei-9-247689. The image sensor disclosed therein uses an XY-addressing type image sensor capable of directly reading pixels at designated locations. In the mode for intermittent read, then, it also uses a signal processing circuit for reading four pixels of the pixels at filter locations of same color and computing an average thereof so as to obtain signals in a mosaic filter pattern identical to that without being thinned out. In the case of CCD image sensor incapable of such reading, it is a common method to obtain a vertical average by adding current values in the vertical direction and at the same time to effect an intermittent read.